only in the first set, speed was less, so I don't think it had to do with the roof ....

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ESPN reported that Federer's average 1st serve went from 120 mph before the roof closed to 125 after. That does not square at all, obviously, with the stats you've got here, from the official Wimbledon site. That site has Federer's fastest serve at 130, but his average was not as high as 120-125.

Semifinal
Djokovic got back 57 of Federer’s 101 good serves: 56.4%Federer got back __ of Djokovic’s 113 good serves: __%

(those stats are from Wimbledon.com and the New York Times tennis blog)

Final
Murray got back 99 of Federer’s 128 good serves: 77.3%
Federer got back 107 of Murray’s 156 good serves: 68.6%

I got stats for the final by using a graphic that was shown in the fourth set. At 2-all, 15-love, right after Murray forces a BH return error, the graphic had Murray with 43 unreturned serves and Federer with 25. I counted to the end – including aces in my count, which I think is the way this is done though I'm not absolutely certain – and finished with Murray at 49 and Federer 29.

The graphic makes it look like Murray was doing nearly twice as well as Federer in serving unreturned serves. That's because it's a simple count of how many serves were unreturned; it does not take into account the fact that Murray served a lot more points in the match than Federer did. When you convert the counts to the percentages above, there was not much of a difference between the two players.

ABMK, even though Federer had more mph on his serves in the semifinal, compared to what he served at Murray, I think these numbers support your argument that Murray returned better than Djokovic (btw I'll have more extensive replies to your posts later).

Federer's second serve was really humming in the semifinal, so if anyone counts the return errors in this match it would be useful to know how many of his second serves went unreturned. If a LOT of Djokovic's return errors occurred on second serve then we might have to give more credit to Federer for making Djokovic's returning look worse than Murray's.

Anyone have those numbers that I'm missing for Federer in the semi?

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At 2-5 in the 4th, with djoker serving @ at 15 all, they showed this stat :

returns % in play :

federer : 68%
djokovic : 57%

djokovic put in 5 more serves after that, of which federer put 3 back into play

djokovic served a total of 115 points, including 2 DFs, so that means federer at that time they showed the stat had returned ( 115-2-5 = 108 )

108*68/100 ~ 73 of those ..

so in the end, 76 out of 113 ~ 67.3%

.....

including aces is the right way to go about it ..

don't have a count of the no of errors forced on the 2nd serve by federer in the semi ...

Thanks Krosero. The piece with the Levin, McEnroe, Roddick, Fed quotes is pretty great. I like how Fed scoffs: "...the statistics guys have no clue what an unforced error is," he said. "I had only about half that."

I re-watched this match a couple days ago and had the same reaction I had the first time I watched and saw the very low UE count flash on screen: What!?

BTW, I didn't score it because I don't know how. Can anyone suggest an authoritative guide to differentiating UE, winners and forced errors?

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well no authorative guide, but just some pointers :

for winners , its mostly simple :

clean winners : on which opponent did not get a racquet on
judgement winners : on which the opponent got a very very slight touch on

the judgement b/w what error is forced and unforced is more complicated and disagreements/doubts can occur :

if the error occurred due to pace, spin or angle of the opponent's shot or low bounce or ball dipping at the net or hit at great depth at the baseline or the player was on the run or stretching or if the opponent was at the net near to cutting off the easy angles, I'd say that error was forced

again, basically all cases in which the opponent forced the error in some way

otherwise the error should be classified as unforced ... ( DFs included )

Your method was probably less lenient than the official statistician's.

That's why for comparing the semi with the final it would probably be best to stick to the official UE's, because presumably the same method was used for both matches.

By the official numbers, the final still looks like less quality than the semi (though not by much).

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well, that's what's puzzling me , I don't think I was that strict in counting UEs tbh ... many of those were simple unforced errors, there was no doubt that they were in fact unforced, for example, if you remember the epic rally on one BP on djoker's serve in the 3rd set, there was some brilliant hitting and defense in that rally, but ended with a wild forehand miss from federer when he went for a bit too much trying to hit a FH DTL ...

the stats in the final look alright to me .....Was it the same statistician who did both the matches ?

federer did obviously find it easier vs murray's 2nd serve, but first serve ? I think murray's was better ... not that much of a difference in federer's returning in the semis and finals, but I think he was a bit better in the finals than in the semis

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Now that we have the exact return stats, I'll say that at least per the numbers, Federer's returning looks better in the semis. His rate of "Returns In" was 67.3% against Djokovic and 68.6% against Murray, not a great difference.

The great difference IMO is that Djokovic was serving better than Murray. Novak's average first serve was 120 mph, just 1 mph less than Murray's. But the average second serve was a significant difference: Djok 95 mph and Murray 88 mph.

Murray's always had a bit of a problem on second serves; Federer was swiping at them. (Novak's also taken advantage of Murray's second serve, eg, 2012 AO).

So was Federer's quality of return really higher in the final, or was it made to seem that way by how effectively he could attack Murray's second serve?

In these matches I don't think the argument works. I had forgotten how many times Federer came to net in the final: he had 68 approaches, nearly three times what he had against Djokovic. That, by itself, would not leave much room for baseline rallies in the final.

And now that we got the missing numbers for these matches, we can actually calculate how many baseline rallies there were. Just exclude all the aces, double-faults, net approaches and return errors, and you should have the # of baseline rallies almost exactly (it's not completely exact because we don't know if there were any points in which both players made approaches: but those points are rare).

So this is what I got:

86 baseline rallies in Fed/Djokovic: 40% of all points played.
99 baseline rallies in Fed/Murray: 34% of all points played.

So Fed/Murray may or may not have had better quality of returning than Fed/Djok, but even if it did, the result was not a greater number of baseline rallies leading to more UE's. Fed/Djokovic was the match that was played more from the baseline: and yet it's the match with lower UE's.

The returning in the final might have produced more baseline rallies, but Federer's charging the net essentially prevented that.

Now that we have the exact return stats, I'll say that at least per the numbers, Federer's returning looks better in the semis. His rate of "Returns In" was 67.3% against Djokovic and 68.6% against Murray, not a great difference.

The great difference IMO is that Djokovic was serving better than Murray. Novak's average first serve was 120 mph, just 1 mph less than Murray's. But the average second serve was a significant difference: Djok 95 mph and Murray 88 mph.

Murray's always had a bit of a problem on second serves; Federer was swiping at them. (Novak's also taken advantage of Murray's second serve, eg, 2012 AO).

So was Federer's quality of return really higher in the final, or was it made to seem that way by how effectively he could attack Murray's second serve?

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well , the first statement I made after re-watching was that I think federer returned equally well in both

federer could and did attack murray's 2nd serve more, but in doing so, he missed quite a few more 2nd serves than he did vs djoker where he didn't go after the djoker 2nd serve as much ...

In these matches I don't think the argument works. I had forgotten how many times Federer came to net in the final: he had 68 approaches, nearly three times what he had against Djokovic. That, by itself, would not leave much room for baseline rallies in the final.

And now that we got the missing numbers for these matches, we can actually calculate how many baseline rallies there were. Just exclude all the aces, double-faults, net approaches and return errors, and you should have the # of baseline rallies almost exactly (it's not completely exact because we don't know if there were any points in which both players made approaches: but those points are rare).

So this is what I got:

86 baseline rallies in Fed/Djokovic: 40% of all points played.
99 baseline rallies in Fed/Murray: 34% of all points played.

So Fed/Murray may or may not have had better quality of returning than Fed/Djok, but even if it did, the result was not a greater number of baseline rallies leading to more UE's. Fed/Djokovic was the match that was played more from the baseline: and yet it's the match with lower UE's.

The returning in the final might have produced more baseline rallies, but Federer's charging the net essentially prevented that.

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well, my argument was two pronged :

1. more returns in the finals resulting in more rallies ( not necessarily baseline ) , as we can see murray got in quite a few more returns and federer's % in was about the same as in the semis .... UEs can happen at the net as well , though not that many did in this particular final ...

2. the UE stats in the semi are off ( which I confirmed for myself by watching ), the UE stats in the final seemed ok to me going by my impression of watching the match ( again, can confirm only if I watch that match again )

clean winners : on which opponent did not get a racquet on
judgement winners : on which the opponent got a very very slight touch on

the judgement b/w what error is forced and unforced is more complicated and disagreements/doubts can occur :

if the error occurred due to pace, spin or angle of the opponent's shot or low bounce or ball dipping at the net or hit at great depth at the baseline or the player was on the run or stretching or if the opponent was at the net near to cutting off the easy angles, I'd say that error was forced

again, basically all cases in which the opponent forced the error in some way

otherwise the error should be classified as unforced ... ( DFs included )

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Thank you. Thinking of Fed's comment on unforced errors. Is it possible that the same forcing shot hit by player A is an unforced error off the racquet of player B but an forced error off the racquet of player C? In other words, if player B is so skilled at returning forcing shots, is it possible that he is given an unforced error for failing to do so, while player B, not quite so skilled but failing to return the same shot, is given a forced error instead. If so, one would think that the great players, like Fed complained, are scored with more unforced errors than they deserve. But I guess for this discussion it doesn't matter, as we're mostly comparing great players.

Your point about surface affecting AM is well taken. You say, for instance, that fast/low-bouncing surfaces tend to have higher AMs. The reason you give for this seems to be twofold: (1) it's easier to execute aggressive plays on fast/low-bouncing surfaces; and (2) netplay is more common on fast/low-bouncing surfaces. Both of these two aspects (easier to force plays, more netplay) seem to positively affect AM, yet you talk as if matches played on the same surface (with the same speed) are roughly comparable with respect to AM. This would only be true if the amount of netplay is roughly constant between matches on a given surface.

It's not clear to me that their is this constancy - especially if we look across eras. Compare Borg-Vilas or Djokovic-Nadal at the FO to Laver-Rosewall. The former pairs remained almost exclusively at the baseline, while the latter approached the net in most points. I include Djokovic-Nadal because, while both camped out on the baseline, they also both go for winners when they have an opening, perhaps in contrast to the more conservative play of Borg-Vilas. This is worth mentioning because I'm going to guess Laver-Rosewall would have the highest AMs of the three pairs due to less unforced errors, but I don't want this attributed to the 'rally-all-day' style of Borg-Vilas. Rather, I think, Laver-Roswall will have the higher AMs than the other pairs because they had less opportunity to hit unforced errors due to the frequent net approaches. This would be the case even though the surface is held relatively constant.

You've talked about this yourself, and the lesson I think is that one can only use AM to compare match quality when holding the surface and level of net play relatively constant. Otherwise AMs can be easily inflated or deflated by factors unrelated to quality of play.

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These are all real issues and because it's late at night I can't give a detailed reply. Some basic points though: so far I have not used AM's across eras. Same would go for winner/error differentials (which I've seen some posters do). There are too many variables.

The comparisons I like to do are matches on the same surface, preferably in the same venue and featuring the same two players: like the 3 Fed-Nadal Wimbledon finals; or the 5 straight years that Djokovic and Federer met at the USO; or the Fed-Delpo matches in '09. You can see just from the posts above how complicated the issues get even when variables are controlled this tightly

I have a feeling we'll be talking again about baseline play vs net play. Contrasting styles do present complications.

However, the stats are not always impacted the way you would expect. We all keep saying that long rallies tend to produce UE's more than matches filled with net-rushing: and that's true. But only up to a point. It doesn't always work out that way.

Take the two USO finals that Lendl and Wilander played in 1987-88. In '88 Wilander came in over 130 times, and there was a lot more net play than in the first meeting.

The first year approximately 27% of all the points were baseline rallies. The next year it was only 20%, but it's the '88 match that has the higher UE's and the lower AM's.

And above we were just comparing Federer's semifinal and final at Wimbledon last year. There was significantly more net play in the final, more baseline play in the semi: yet the final has higher UE's and lower AM's.

I'll have a look to see if there are more such cases. For now let me just caution that we should be careful about saying that net-rushing matches will have fewer UE's than wars of attrition between defensive players. Net-rushing is an aggressive play. Aggressive players tend not to keep their UE's down, because that's not their goal; and they're always trying to force the issue.

About Laver: I don't expect a Laver/Rosewall match at RG to have fewer UE's, and higher AM's, than Borg-Vilas and Nadal-Djokovic. That could be the case; I don't have the stats for Laver-Rosewall. But Laver did not temporize, and he did make errors as a result. On a slower surface that would make it harder for him to hit winners, you would expect him to make a good number of UE's and possibly a lot.

1. more returns in the finals resulting in more rallies ( not necessarily baseline ) , as we can see murray got in quite a few more returns and federer's % in was about the same as in the semis .... UEs can happen at the net as well , though not that many did in this particular final ...

2. the UE stats in the semi are off ( which I confirmed for myself by watching ), the UE stats in the final seemed ok to me going by my impression of watching the match ( again, can confirm only if I watch that match again )

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OK, I had assumed that you meant baseline rallies, because that's the assumption we've all been working with: baseline rallies are more likely to end in an UE.

Yes if you get a chance to do the final that would be great, because then the same method is being used.

We have been debating whether it is possible for the two players to raise their level of play without changing the AM's.

I would like to present a hypothetical scenario in which two players playing on two occasions on the same surface exhibit different level of play yet their calculated AM’s stay the same.

It is open to debate if such a scenario is realistic.

On the first day they played an average match; winners, forced and unforced errors were counted, and the AM's were calculated.

On the second day they played an excellent match, however the number of winners, forced and unforced errors was the same as on the first day (for the sake of simplicity I assume that the number of points in both matches was the same). How is it possible?

Winners;
The first player was hitting great shots, however the second player was also defending better than previously (had the second player been playing as well as on the first day, the first player would have had more winners than on the first day, had the first player been playing as well as in the first match he would have had less winners than in the first match). As a result the first player had the same number of winners on both occasions, and the same applies to the second player.

Forced errors;
Generally the same logic applies to forced errors. Both players committed the same number of forced errors as during the first match, however the shots that forced these errors were of the higher quality than the shots that forced errors in the first match.

Unforced errors;
Generally the same logic applies to unforced errors. Both players committed the same number of unforced errors as during the first match, however the points which ended in unforced errors were of the higher quality than points which ended in unforced errors in the first match. We have already mentioned that points that end in an unforced error may be of different quality (e.g. long neutral rallies versus double faults or return errors or short neutral rallies).

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Very interesting, I'm going to give this some thought. A little mind-bending for me at this time of night.

OK, I had assumed that you meant baseline rallies, because that's the assumption we've all been working with: baseline rallies are more likely to end in an UE.

Yes if you get a chance to do the final that would be great, because then the same method is being used.

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just adding to my previous post :

1. federer having better success vs the weaker murray 2nd serve is already reflected in a significantly higher % of 2nd serve return points won than vs djoker's 2nd serve ... just that federer attacked the murray 2nd serve bit more resulting in a few more missed returns than if he would've just put them back into play ... different methods in different matches, but both appropriate for the kind of 2nd serves he was facing and both almost equally effective IMO ...

2. I just mentioned rallies, not just baseline rallies ... As we know , SnV points leave less chance for UEs, but there were very few SnV points in the final ..... most of the net points were points constructed from the baseline and then the players approached the net ... that does leave quite a bit of chance for UEs ... the % of success at the net does indicate well constructed points and very good net play for most part .....

Thank you. Thinking of Fed's comment on unforced errors. Is it possible that the same forcing shot hit by player A is an unforced error off the racquet of player B but an forced error off the racquet of player C? In other words, if player B is so skilled at returning forcing shots, is it possible that he is given an unforced error for failing to do so, while player B, not quite so skilled but failing to return the same shot, is given a forced error instead. If so, one would think that the great players, like Fed complained, are scored with more unforced errors than they deserve. But I guess for this discussion it doesn't matter, as we're mostly comparing great players.

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well, I would say it is possible, though not deliberately, but at a subconscious level ; you'd expect great players to miss less ....

see for example rafa missing the BH pass vs djoker in the final set of the Aussie Open final in AO 2012 ... it was a doable pass , even more so for rafa, though not an absolute gimme ... say if roddick had missed it, how many would've raised eyebrows ? and roddick was no slouch himself ...

just that one has to be be vigilant enough while making these judgements ...

1. federer having better success vs the weaker murray 2nd serve is already reflected in a significantly higher % of 2nd serve return points won than vs djoker's 2nd serve ... just that federer attacked the murray 2nd serve bit more resulting in a few more missed returns than if he would've just put them back into play ... different methods in different matches, but both appropriate for the kind of 2nd serves he was facing and both almost equally effective IMO ...

2. I just mentioned rallies, not just baseline rallies ... As we know , SnV points leave less chance for UEs, but there were very few SnV points in the final ..... most of the net points were points constructed from the baseline and then the players approached the net ... that does leave quite a bit of chance for UEs ... the % of success at the net does indicate well constructed points and very good net play for most part .....

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1. Federer gained something by being aggressive with Murray's second serve, and the cost was a few more missed serves, because he was going for them. Agreed on that. I think you're saying that when we look at the fact that his Return In % was basically the same as what it was in the semis we should take the missed serves into account. He may have missed them, but he also gained something by attacking the second serve. I could see that. There's a good case his returning quality in the two matches was very similar.

2. Not sure I understand you here. Our working assumption is that net play of any kind, not just SV, reduces the chances for UE's because only 1 player (the one rushing the net) can now make an UE; the defender will either make a winner or a forced error.

I don't think you're saying that SV net play results in more UE's than net play behind approaches (or are you?)

Keep in mind we were debating why there were more UE's scored in the final than in the semi. That's the issue I'm talking about.

Are you saying that the baseline rallies in these matches -- the points on which all 4 players stayed back throughout the point -- were different in the final, and more likely to end in UEs, because Federer and Murray were trying to get into net?

On the matches that you've charted, did you find that the average AM varied according to the era? For example did you believe 1968 to 1985 had different AMs than 1985 to 2000 and that would differ from 2001 to the present?

well, I would say it is possible, though not deliberately, but at a subconscious level ; you'd expect great players to miss less ....

see for example rafa missing the BH pass vs djoker in the final set of the Aussie Open final in AO 2012 ... it was a doable pass , even more so for rafa, though not an absolute gimme ... say if roddick had missed it, how many would've raised eyebrows ? and roddick was no slouch himself ...

just that one has to be be vigilant enough while making these judgements ...

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Yeah, your Rafa vs. Roddick backhand error is just the type of thing I was thinking of.

We have been debating whether it is possible for the two players to raise their level of play without changing the AM's.

I would like to present a hypothetical scenario in which two players playing on two occasions on the same surface exhibit different level of play yet their calculated AM’s stay the same.

It is open to debate if such a scenario is realistic.

On the first day they played an average match; winners, forced and unforced errors were counted, and the AM's were calculated.

On the second day they played an excellent match, however the number of winners, forced and unforced errors was the same as on the first day (for the sake of simplicity I assume that the number of points in both matches was the same). How is it possible?

Winners;
The first player was hitting great shots, however the second player was also defending better than previously (had the second player been playing as well as on the first day, the first player would have had more winners than on the first day, had the first player been playing as well as in the first match he would have had less winners than in the first match). As a result the first player had the same number of winners on both occasions, and the same applies to the second player.

Forced errors;
Generally the same logic applies to forced errors. Both players committed the same number of forced errors as during the first match, however the shots that forced these errors were of the higher quality than the shots that forced errors in the first match.

Unforced errors;
Generally the same logic applies to unforced errors. Both players committed the same number of unforced errors as during the first match, however the points which ended in unforced errors were of the higher quality than points which ended in unforced errors in the first match. We have already mentioned that points that end in an unforced error may be of different quality (e.g. long neutral rallies versus double faults or return errors or short neutral rallies).

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I think I have to go back to what I said in one of the earlier posts (I forget which one). If a player increases his level of play, it's hard to imagine him not cutting down on his UE's.

With the other kinds of points -- the winners and forced errors -- there's a kind of logic to arguing that the defender, by raising his level, will offset the more successfully aggressive play of his opponent. You give as good as you get.

Not saying I agree that that could happen, but I see where you're coming from.

With the UE's, though, it's different. Those are the kind of errors that have least to do with what your opponent is doing. Those are the kind that you make when your concentration breaks momentarily; or you get physically lazy or something; or you've got a relatively simple shot but because you have a slight flaw in your technique you miss it.

I think we all agree that there are different kinds of UE's, and that sometimes an error is marked down as unforced even when the player commits it after a long, exhausting rally. On those points you could say that your opponent has a lot to do with your error.

But let's leave those ambiguous points aside. I'm talking about the most basic errors in a match: the ones that are entirely due to yourself. Every match has those. No one can play a perfect match.

And if the two players have genuinely raised their level, I can't see how they would not cut down on those types of errors.

I would expect those types of errors to decrease first and foremost, when you're playing well.

Anyway, once the UE's decrease, the AM's increase.

Still can't see how increased level of play can fail to raise AM's -- though it's still an interesting question!

On the matches that you've charted, did you find that the average AM varied according to the era? For example did you believe 1968 to 1985 had different AMs than 1985 to 2000 and that would differ from 2001 to the present?

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Really difficult to say with my limited data.

If I do find a pattern, we can talk about it, but there's none that I've noticed.

The one thing I can say with confidence is that UE counts are all over the place, the farther back you go. (I would guess that the farther back you go, the less agreement there was on how to score UE's). That makes it very suspect to compare official UE counts between eras.

Thank you. Thinking of Fed's comment on unforced errors. Is it possible that the same forcing shot hit by player A is an unforced error off the racquet of player B but an forced error off the racquet of player C? In other words, if player B is so skilled at returning forcing shots, is it possible that he is given an unforced error for failing to do so, while player B, not quite so skilled but failing to return the same shot, is given a forced error instead. If so, one would think that the great players, like Fed complained, are scored with more unforced errors than they deserve. But I guess for this discussion it doesn't matter, as we're mostly comparing great players.

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Well I remember a statistician years ago saying something similar. It was a long time ago so my memory is vague, but this was the idea: when you see Lendl miss a shot you have to consider whether a player at his level should be making that shot more often than not.

He went on to say it was a highly subjective process.

I think the scoring of UE's could be more objective if it were based as much as possible on physical movements of the players and the ball. I really think that if you start judging an error according to your own expectation of whether this champion should make the shot, that is a sure way to introduce bias into the stats. One statistician who has a high opinion of Lendl will judge the error differently from the statistician who has a lower estimation of Lendl.

Or take it down to the level of strokes. Different people have differing opinions on Federer's BH, and differing opinions on how it compares to his FH. You might expect the Federer FH to stand up to a certain shot, but not expect the same of Federer's BH: because you know beforehand that Federer's FH is stronger.

That's backwards IMO: the errors should be judged objectively, and then the stats can illustrate which stroke (or which player) is better. If you judge each stroke, or player, by preset standards, the stats lose all capacity to say anything.

I think all such opinions about particular players and their particular strokes should be left out of the scoring process as much as possible. IMO it would be far more objective to judge an error based on what's happening with the ball and the player, forgetting what the player's name is (if you can do that). Just judge it on how hard the ball is hit, or how much spin or angle; how far the player had to run to get it; whether one player is at net; etc. Physical facts about the body and the ball.

To the extent that this can be done, the resulting stats would then be able to illustrate which stroke, or even which player, is stronger in this situation, in that situation, etc.

1. Federer gained something by being aggressive with Murray's second serve, and the cost was a few more missed serves, because he was going for them. Agreed on that. I think you're saying that when we look at the fact that his Return In % was basically the same as what it was in the semis we should take the missed serves into account. He may have missed them, but he also gained something by attacking the second serve. I could see that. There's a good case his returning quality in the two matches was very similar.

2. Not sure I understand you here. Our working assumption is that net play of any kind, not just SV, reduces the chances for UE's because only 1 player (the one rushing the net) can now make an UE; the defender will either make a winner or a forced error.

I don't think you're saying that SV net play results in more UE's than net play behind approaches (or are you?)

Keep in mind we were debating why there were more UE's scored in the final than in the semi. That's the issue I'm talking about.

Are you saying that the baseline rallies in these matches -- the points on which all 4 players stayed back throughout the point -- were different in the final, and more likely to end in UEs, because Federer and Murray were trying to get into net?

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Net play does reduce the chance of UEs, but even in this there are variations, SnV reduces it drastically. In case of a point constructed from the baseline and then the net approach made, there is still quite a bit of chance for the players to commit the UE - while the point is being constructed . Therefore it isn't logical to completely exclude those net points either from the semi or the final while computing unforced errors in rallies ...

In case of a point constructed from the baseline and then the net approach made, there is still quite a bit of chance for the players to commit the UE - while the point is being constructed . Therefore it isn't logical to completely exclude those net points either from the semi or the final while computing unforced errors in rallies ...

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There's some confusion here. I'm not trying to exclude net points from any total count of the UE's. I'm excluding net points from baseline rallies.

A net rusher makes more UE's if he's following his serve to net rather than following an approach? I doubt it; I'd like to see some stats supporting it.

There's some confusion here. I'm not trying to exclude net points from any total count of the UE's. I'm excluding net points from baseline rallies.

You're argument here is completely unclear.

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no ...... its the other way around ... I'm saying there is more chance of UE in the 'whole' point when net rusher is following an approach rather than his serve ...please read what I wrote again ...

yeah, I know you were trying to exclude the net points from baseline rallies .....

But like I said, I was talking about errors in rallies, not just @ the baseline ....

my argument was that there were more returns in play in the finals and most of the net points were NOT SnV in the finals, therefore that leaves ample scope for UEs in all those points ... ( including rallies at the baseline and those points that were constructed from the baseline and ended up in a net approach )

For no particular purpose:
(The average AMs on the men's side for seven rounds of 2005 AO: Winner 22.5%; Loser 11.0%)

Not sure how much meaning is here, but it appears that Murray, who's performance in the 1st round was lauded by the press, faced weak opposition, while five other players posted 29+ AM's even though their opponents played at a level that was near the 2005 tournament average (10+ AMs). Tomic appears to have played his 1st rounder like an elite player and also to have played at a high level in the 2nd round, defeating Brands who posted a higher AM than Tomic in the match.

no ...... its the other way around ... I'm saying there is more chance of UE in the 'whole' point when net rusher is following an approach rather than his serve ...please read what I wrote again ...

yeah, I know you were trying to exclude the net points from baseline rallies .....

But like I said, I was talking about errors in rallies, not just @ the baseline ....

my argument was that there were more returns in play in the finals and most of the net points were NOT SnV in the finals, therefore that leaves ample scope for UEs in all those points ... ( including rallies at the baseline and those points that were constructed from the baseline and ended up in a net approach )

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I see now that we were referring to different things. When I say that net play reduces the chances of an unforced error, I mean that if we looked at the final strokes that ended a net point, we would be less likely to find UE’s there than if we look at the final strokes of baseline rallies. So I presume that if we look at all volleys made at the net, we’re not going to find more volley UE’s behind the serve than we will find volley UE’s behind approaches.

What you meant by chances of an UE is the potential for an UE to occur if you’re just thinking of the two players as they begin their point: if they get into a long baseline rally there’s a great chance that they’ll end up making an unforced error; and there’s also a potential if they’re trying to get to the net, but less so, because those points might be shorter; and there’s the least chance of all for an UE to occur if the server decides right away to follow his serve to net.

It’s an interesting argument, and I see the logic now: Murray, by returning better than Djokovic, put more balls into play -- and once the ball is in play the point might end in an UE (at net or the baseline). Therefore the Murray final had a higher number of UE’s than it would have had if Murray had returned as “badly” as Djokovic, who often could not get the serve back in play. The higher UE’s meant lower AM’s than those of the semifinal.

However I’ve worked out the numbers, and I think Murray’s superiority in the service returns -- if it was responsible for producing any UE’s -- cannot have produced more than 2 or 3 extra UE’s.

The Murray/Fed match needs to drop more than 2 or 3 of its UE’s. It would need to drop 22 of its unforced errors, in order to equal the AM’s of Fed/Djokovic.

Okay, let me say this about your argument. I do not think it can work if we’re talking about Murray returning better than Djokovic because he made fewer UNFORCED errors on the return. I said this above to Burstyn: if a player is cutting down his UE’s on the return and putting more balls into play, he is lowering the UE’s of the match as a whole, and the AM’s will rise. That’s not the problem with Murray/Federer: we’re looking for a way to explain how Murray’s returning might have ADDED to the UE count and lowered the AM’s.

But I can see how your argument might work if Murray’s better returning cut down on the number of FORCED errors. You mentioned that yourself in a post above: if Murray is able to return the kind of powerful serves that forced Djokovic into return errors, then he’s putting the ball back into play without decreasing the # of UE’s in the match: and those extra rallies might end in some UE’s. Thus adding to the UE’s of the match as a whole.

(I don’t think the argument really works for Djokovic/Fed/Murray, but I’d like to apply it to matches between HUGE servers who have a weak overall game and who can be counted on to make unforced errors if you can only get their huge serves back in play. But I’ll leave that for another post.)

I concede that Murray’s strength on the return does happen to be his ability to get serves back in play. Maybe Djokovic has the more aggressive return: but Murray got more of Federer’s serves back in play. We’re talking about big, forcing serves: not the kind of serves on which the receiver can make an UE trying to return it. Murray and Djokovic actually had nearly identical numbers, as far as UE’s on the return (those numbers available on the Wimbledon site). It’s on the big, forcing serves that Murray must have done better than Djokovic.

So in a way this is a perfect test case.

The main problem is that Murray cannot have put nearly enough serves back into play -- not nearly enough to account for the difference in AM’s between the final and the semifinal. He needed to put enough serves back in play for 22 EXTRA unforced errors to appear. And since only a fraction of rallies end in unforced errors, you can imagine that the number of EXTRA rallies that he needed to create would be far more than 22.

In the actual matches, the number of powerful serves that Murray put back in play -- serves of the kind that Djokovic could not return -- was probably somewhere around 10 (I’ll show that below). And only a fraction of those -- if any -- would be likely to end in UE’s.

You can easily find out the number of rallies (baseline or net) in these matches (Total Points minus Unreturned Serves minus DF’s).

And you can find out the number of UE’s that occurred in the rallies (Total UE minus DF’s minus UE’s on the return).

Semifinal -- 133 rallies, of which 6 ended in UE’s (5%)
Final -- 206 rallies, of which 35 ended in UE’s (17%)

So of the extra rallies that Murray created with his return, you’d have to say that only about 17% of them were likely to end in UE’s.

And how many extra rallies did Murray probably create? Well if you lower his rate of “Returns In” to make it exactly equal to Djokovic’s (56%), you’d give Murray 17 more return errors. So is 17 the number of extra rallies that Murray’s quality return created? Not quite, because we agreed that Murray had weaker serves to deal with than Djokovic did (Novak faced higher MPH from Federer). So that’s why I said 10 before. As a compromise. Ten extra rallies produced by the quality of Murray’s returning.

And 17% of 10 extra rallies comes to 2 extra UE’s.

That would increase the combined AM’s of the final by less than 1%.

So I think if the AM’s of the final are lower than those of the semifinal, we’re looking at two possible causes:

1) the level of play in the final was genuinely lower
2) there is a discrepancy in how the UE’s were scored in these two matches
3) the AM method does not describe these two matches very well

No women's matches have been mentioned yet, I don't have any AM's. What do you think might be a candidate for highest, maybe Graf-Zvereva? I couldn't find the UE's for that one.

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Serena Williams and Sloane Stephens were both around 34% in their first rounders at AO, both very one-sided matches.

Krosero, I was thinking of posting the top 10 men's AM's for each round of the tournament in this thread, maybe adding them to the 1st round post I made above. But it's a bit off topic. Your thread, your call.

Serena Williams and Sloane Stephens were both around 34% in their first rounders at AO, both very one-sided matches.

Krosero, I was thinking of posting the top 10 men's AM's for each round of the tournament in this thread, maybe adding them to the 1st round post I made above. But it's a bit off topic. Your thread, your call.

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Not off-topic, please post them. We'll see what we can make of them.

Yeah probably in that post above would be best, so they're easy to study all at once.

yes, that was my point .. If you cut down on the no of forced errors by getting those serves back into play, that increases chances for the UEs ..

Coming to the return UEs, I don't know again WTH the statistician was doing ...

I have the stats till the 3rd set

murray only committed 2 UEs on the return ... they have him @ 8 UEs on the return until the 3rd set ...

federer only had about 4-5 UEs on the return ( don't remember exactly and don't have the stats with me right now ) ... they have him at 11 UEs on the return until the 3rd set

Also have a look at the return winners column there : 19 return winners for federer in the whole match ... now, really ?? he had only about 12-15 returns winners vs SnVing sampras in their 5-setter in 2001 (IIRC ) and we know its easier to hit return winners vs SnVers than against those who stay back

they also have murray @ 9 return winners .... till 3rd set, I have them both making only a couple of return winners till the 3rd set ( I haven't noted that stat down, but I recall that very clearly )

also chew on this :

murray had ~77% of returns back into play ... federer made 131 serves out of which 3 were double faults ... so 128 serves in which murray could have a chance to get the ball back into play

128*77/10 ~ 99

so he missed returning 29 of the serves from federer
the ace count is 12

so that leaves room for 17 (return errors+service winners ) ... if he had 9 unforced errors on the return, that leaves room for only 8 (forced return errors+service winners ) ... now really ?

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now coming back to the total unforced error count, the unforced error count till 3 sets in the official stats is fairly close to mine unlike in the semi where there is more discrepancy .. I will post the full stats once I'm done with the final set ...

Generally, I would pick Fed over any player in history, but only when/during that unbelievable run at #1 during 04-08 +/-. Now, altho hes still incredible, just not as incredible .

I never followed the women too closely, but I would pick Serena. Too dominating in almost all qualities.

-I feel a question like this is so contextual, its almost impossible to provide an accurate answer, however. The game is constantly changing in every aspect, so, I think it would be hard to know how a player today or before, would/could be effected and how they would perform. Tough to deny Roger in any situation, altho he did step into the game as the last gen of great(s) left...

I have these UE stats for the final b/w fed and murray at Wimbledon in 2012 :

by set:

federer : 16,9,6,8 - total of 39
murray : 7,5,7,8 - total of 27

wimbledon.org has

federer : 16,8,6,8 - total of 38
murray : 5,4,8,8 - total of 25

going by my UE count :

federer's AM = 29.5%
murray's AM = 24.7%

no of return unforced errors :

I have federer making 8 return unforced errors, murray making 3 return unforced errors ( wimbledon.org has fed at 16 and murray at 9 !! )

The stat about return winners at wimbledon.org is obviously wrong ...(19 for fed and 9 for murray )

when federer hit a return winner at 5-3,15-40 in the 4th set, they showed federer : 3 return winners, murray : 1 return winner ... no other return winners after that ....

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I just put your stats together here for comparing the two matches.

On service returns: by your count Murray made 4 less UE's than Djokovic. That would mean that Murray's superiority over Djokovic as a returner actually cut down the total UE's in the final and raised the AM's of the match.

Overall: using your total count of UE's, the two matches were of similar quality, the semifinal only slightly higher.

I'm glad you took the UE's because it shows how much discrepancy there can be between any two statisticians.

I don't think the problem is the concept of the UE as such. The concept is fine; but there is no standardization of stats in tennis. No universal conception of how UE's should be counted.

As you know, I've seen endless problems even with Winners, which you would think are basically straightforward. I've seen the term used to refer to clean aces and winners the way most of us use it. But I've also seen boxscores, in this era, that use the term to mean the number of groundstroke winners, no volleys included, no service included (as they did at the Olympics in '08 ). RG once used "Winners" to mean all points won on serve. And though most statisticians include service when reporting the total winners, there is still discrepancy because there are multiple definitions of what a service winner is.

Lack of standardization is a major problem in tennis stats.

I don't know what those 'return winners' at Wimbledon.com refer to.

One guess: maybe they refer to all returns that went past the server cleanly (what you counted, ABMK) or forced an error from the server. I would call all those returns "winning returns." It's a little like the concept of the service winner: you're counting all winning serves, whether they go by cleanly or they force the receiver into an error.

well, that's what's puzzling me , I don't think I was that strict in counting UEs tbh ... many of those were simple unforced errors, there was no doubt that they were in fact unforced, for example, if you remember the epic rally on one BP on djoker's serve in the 3rd set, there was some brilliant hitting and defense in that rally, but ended with a wild forehand miss from federer when he went for a bit too much trying to hit a FH DTL ...

I wouldn't call that a simple unforced error; I could see it being scored either as forced or unforced.

Djokovic is changing the direction of the ball by going DTL, not a percentage play. He's very good at that particular shot and I'm sure you've seen him do damage to Federer and other players with it. But it's not percentage; and he's trying to make something happen when he uses it. I mean more than throwing in a slice to change the pace a little: I mean trying to make his opponent run after an unexpected shot.

Federer lost his balance there a little and made a wild shot -- possibly because he saw Djoker in that corner ready to receive any DTL shot Federer might give him. So maybe he tried to go too close to the line, or changed his mind at the last minute. Who knows -- but I think Djokovic outmaneuvered Federer on that point. He covered the space where his opponent wanted to put the ball -- kind of like a net player covering the sideline and forcing a defender's passing shot to go wide.

Anyway he did make Federer run, and that's one of the factors usually mentioned when statisticians talk about how to score UE's. I would also consider things like a player changing the direction of the rally to go DTL (not a percentage play).